PROOF OF EXISTENCE AND THERMOCHEMICAL CHA RACTERIZATION OF THE GASEOUS MOLECULE VOCL2

By use of the Knudsen-cell mass spectrometry the existence of VOCl2(g) is proven. Lines of fragmentation are set up for VOCl3(g). The vapor above V2O3(s) with Cl-2(g) is examined. The sublimation of VOCl2 is me asured at a temperature of 550 - 620 K. By 2nd law calculations the he at of sublimation is defined. The calculation for the gaseous VOCl2 le ads to Delta(B)H degrees(VOCl2(g), 298 K) = -(130,4 +/- 1,5) kcal . mo l(-1). The influence of VOCl2(g) for chemical vapor transport reaction s of vanadium oxides with Cl-2 is discussed by equilibrium calculation s.